Source: Aviation, Space, and Environmental Medicine

Vol. 78, No. 11, November , 2007, Page 1055 – 1059

Note: in 2010, the FAA changed its p0licy and use of certain SSRIs is now allowed under certain conditions, on a case-by-case basis – See Press Release

Introduction:

Selective serotonin reuptake inhibitor (SSRI) antidepressants are popularly prescribed, but these drugs are not currently approved for use by U.S. civilian aviators. In a 2003 study, the presence of 4 SSRIs — citalopram, fluoxetine, paroxetine, and sertraline — was reported in 61 pilot fatalities of civil aviation accidents that occurred during 1990 – 2001. However, it was not known whether these pilots had disqualifying psychological conditions, including depression, and had properly reported the use of the antidepressants.

Methods:

The aeromedical history of the pilots was retrieved from the Federal Aviation Administration’s (FAA’s) Aerospace Medical Certification Database; additionalpilot medical information and the cause/factor of the accidents were obtained from the National Transportation Safety Board’s (NTSB’s) Aviation Accident Database. Results: There were 59 pilots who had medical records in the FAA’s Certification Database. Disqualifying psychological conditions were self-reported in the past examinations of only 7 (12%) of the 59 pilots, and the use of an SSRI was reported by 3 of the 7 pilots. In later examinations, 6 of the 7 indicated that they were free from the conditions and not taking SSRIs; thus, they were reissued medical certificates. Such conditions and/or drug use were not self reported in the aeromedical records of the remaining 52 (88%) pilots.

Nevertheless, the NTSB investigations revealed that 12 (20%) of the 61 pilots had a history of a psychological condition and/or an SSRI use, as suggested by their personal medical records. Conclusions: These findings reconfirm that SSRIs were used by the aviators but were not reported in their last aeromedical examinations.

SELECTIVE SEROTONIN reuptake inhibitors (SSRIs) are a new generation of effective medications for treating depression ( 4,5 ). In comparison to older antidepressants, SSRIs have a higher therapeutic index and are better tolerated by patients ( 4,5,20,24 ). These antidepressants are also used widely in a variety of psychiatric and non-psychiatric conditions ( 4,5,20,24 ). Therefore, SSRIs are popularly prescribed (19), allowing them to remain in the top 200 drugs of the most dispensed prescriptions in the U.S. pharmaceutical industry ( 1,2,19 ). However, SSRIs are not currently approved for use by U.S. civilian aviators ( 14,22,23 ).

Aviation safety concerns have been raised for the risk potential of depressed and untreated pilots and for the pilots receiving SSRIs without informing the aviation medical examiners (AMEs) or the Federal Aviation Administration (FAA) ( 16,17,23,26 ). Furthermore, based on the pilots’ telephone inquiries database of the Aviation Medicine Advisory Service ( 17 ), it has been reported that, when instructed about the current regulations banning the use of SSRIs by airmen, 59% of the pilots preferred to refuse the medication and continue to fly. However, about 15% said that they would prefer to take the

medications without informing the FAA ( 17 ). Another safety issue that has been reported by FAA officials shows that the problem is not solely with the pilots’ incorrect decision, but, in some instances, with AMEs’ practices as well ( 23,25 ).

Findings from such analyses are maintained in the CAMI Toxicology Database. In a 2003 study by Akin and Chaturvedi ( 1,2 ), the prevalence of SSRIs in civil aviation accident pilot fatalities was evaluated by retrieving necessary information from the CAMI Toxicology Database. These were the drugs that are pharmacologically classified as selective inhibitors of serotonin reuptake — that is, citalopram,

fluoxetine, paroxetine, and sertraline (1,2,4). Accordingly, the 4 SSRIs were found to be present in 61 of 4184 pilot fatalities of U.S. civil aviation accidents that occurred during 1990 – 2001; only 1 of these 4 SSRIs were present in 22 pilots, but other drugs and/or ethanol were also found in the remaining 39 SSRI pilots (1,2).

The use of an SSRI was found to be a contributing factor by the National Transportation Safety Board (NTSB) in 9 of the 61 accidents, but the reports of all 61 accidents were not finalized at the time of the study. Although toxicological findings, flight categories, and pilot certificates of the 61 SSRI-involved pilot fatalities were discussed thoroughly in the study ( 1,2 ), it was not known whether these pilots had disqualifying psychological conditions, including depression, and had properly reported the use of the antidepressants in their past aviation medical examinations. Therefore, as a continuation of the earlier study, the present study was conducted to reveal the medical history of those 61 pilots and the cause/ factors of all the associated 61 accidents.

METHODS

Aviation Medical Examinations

All U.S. civilian pilots flying an aircraft under 14 CFR Parts — for example, Part 91, 135, 121, 137, and 133 — are required to undergo periodic aviation medical examinations and to hold a fi rst-, second-, or third-class aeromedical certification (11,12). Examination reports are submitted to CAMI’s Aerospace Medical Certification Division online and/or through regular mail by AMEs. Additional medical information, such as specialist reports or laboratory test results, is also submitted to CAMI. All submitted information is stored both as hard copies and digitally in the Aerospace Medical Certification Division.

Database Search

The total number of pilot fatality-involved accidents from which CAMI received biological samples for each year from 1990 to 2001 was retrieved from the CAMI Toxicology Database (Oklahoma City, OK); also, the number of SSRI-involved accidents was obtained from the database for each of these 12 yr. Past aviation medical examination reports of each of the 61 pilots with evidence of SSRI use were searched through the CAMI Medical Certification Database (Oklahoma City, OK). Both CAMI databases are physically maintained in a secured environment and only authorized individuals, depending upon their administrative roles, responsibilities, and needs, have access at certain levels of the databases to ensure the security and the confidentiality of pilots’ identities and other associated privacy issues. The authorized individuals are required to use their username and password to have access to the databases.

Additional available personal medical histories of the pilots were obtained through the accident reports from the public-domain NTSB Aviation Accident Database (Washington, DC). Information on the types of airman medical certificates held by these pilots was retrieved from the CAMI Certification Database and from the NTSB Aviation Accident Database. The number of fatal aviation accidents reported by the NTSB for the 1990 – 2001 period was obtained from the public-domain FAA Aviation Safety Information Analysis and Sharing (ASIAS) Database (Washington, DC). The information for the 61 SSRI-related accidents, including the probable cause and contributing factors of those accidents, as determined

and reported by the NTSB, was retrieved from the NTSB Aviation Accident Database. Since the ASIAS

Database includes information primarily associated with registered aircraft accidents, information on unregistered aircraft accidents may not necessarily be included in this database. It should be noted that not all of the pilots involved in the accidents had appropriate airman fl ying and/or medical certificates to fly an aircraft.

Statistics

The proportion (percentage) of the SSRI-involved fatal accidents/ pilot fatalities in the total pilot fatality involved accidents/pilot fatalities per year was calculated for each year from 1990 to 2001. Regression analysis was performed by fitting a linear regression line to the individual proportional values plotted against the corresponding years by using SPSS ® for Windows ® 10.0 (SPSS, Inc., Chicago, IL).

RESULTS

The age of the 61 pilots ranged from 27 to 71 yr (mean: 52.0; SD: 11.3; N [1] 61). The flying experience of the pilots expressed as total fl ight hours was distributed in a wide range of 5 to 25,678 h (mean: 2811.6; SD: 5440.1; N [1] 61). Based upon the available medical records of 59 pilots, the time between the accident and the last aviation medical examination ranged from 2 to 118 mo (mean: 16.7; SD: 18.3; N [1] 59). This group of pilots consisted of 1 woman and 60 men. Professions of the 61 pilots were listed as: businessmen, 21; medical professionals, 13; professional pilots, 6; and others, 10 (ranchers, lawyers, engineers, aircraft mechanics, and retired individuals). The professions of 11 pilots were not known. Of the 13 medical professionals, 2 were psychiatrists and 1 was a psychologist.

Of the 61 accidents, 56 happened in general aviation (Part 91), 2 in air taxi and commuter (Part 135), and 3 in agricultural flights (Part 137) ( 11 ). Of the 56 general aviation accidents, 35 pilots held private

(1 of them had a foreign flying certificate), 10 commercial, 4 airline transport, 3 student, and 1 recreational airman flying certificates. Three pilots were non- certificated. All five pilots of the air taxi, commuter, and agricultural flights held commercial airman flying certificates.

Out of the 61 pilots, 3 held first-class, 12 second-class, and 34 third-class medical certificates (1 of them had a foreign medical certificate) (12). Medical certificates of five pilots had been deferred or denied; certificates of six pilots were expired at the time of the accident; and one pilot did not have a certificate. Two of the second-class medical certificate holders were involved in air taxi and commuter flights and three in agricultural flights. The remaining 56 pilots were involved in general aviation accidents.

The percentages of the SSRI-involved pilot fatalities per year, with respect to the total number of pilot fatalities (cases) per year during the 12-yr period from which post-mortem samples were received at CAMI, suggest an increase in the proportion of fatalities by 2001 — that is, the SSRI-associated fatalities/aviation accidents increased from 0.26% in 1991 to 5.88% in 2001 (Fig. 1). The regression analysis of the proportions of the SSRI-involved fatal accidents/pilot fatalities in the total fatal accidents/pilot fatalities per year was statistically significant and the linear regression line yielded a fine fit (R 2 [1] 0.68; P [1] 0.001).

Medical records of 59 pilots were found in the CAMI Certification Database. The database did not contain information about one pilot who had never received a medical examination. Another pilot had a foreign medical certificate. Of the 59 pilots, 22 had self-reported a history of convictions involving driving under the influence (DUI). Additionally, one pilot had reported a history of alcohol abuse.

Eight pilots were found in the Certification Database with diagnoses related or attributable to psychiatric

disorders or psychological conditions. One of these pilots had failed to report a diagnosis of a disorder/ condition, and it was not discovered by the AME during medical examination. However, the Regional Flight Surgeon’s office did discover information from a court decision and subsequently from the treating physician’s report that the pilot had a history of “attempted suicide.” Of the eight pilots, seven had self-reported a history of psychiatric or psychological conditions; three of these seven pilots had reported the use of an SSRI as well. Of the seven pilots who initially self-reported the history, only one was not reissued a medical certificate after the pilot’s last aviation medical examination, which was conducted 32 mo before being involved in a fatal accident. The other six pilots had declared that they no longer had a disqualifying medical condition and/or they had not been taking a disqualifying medication. Furthermore, the personal medical records of 2 of these pilots and an additional 10 pilots showed that they had been on regular treatment with antidepressants. Of the seven pilots, one had reported a history of “unconsciousness,” one of “mental disorder,” one of “alcohol abuse,” one of “unspecified neurotic disorder” (taking fluoxetine), two of “depression” (one of them was taking paroxetine), and one of “anxiety” (taking sertraline). Also, six of the seven pilots had subsequently reported and/or submitted specialist reports denying that they had the disqualifying conditions or were being treated with the disqualifying medications. Therefore, they were reissued medical certificates. However, one pilot with a diagnosis of depression was deferred by the AME and was not issued a medical certificate. The pilot’s deferred medical examination was conducted 32 mo. before being involved in a fatal accident.

Personal medical records retrieved from the NTSB accident reports indicated that, of the 61 pilots, 9 had a history of the use of an SSRI, 1 of an antidepressant, and 1 of an adult attention deficit disorder (AADD) medication. Of these 11 pilots, A) 4 had the diagnosis of “depression” (2 were prescribed fluoxetine, 1 citalopram, and 1 paroxetine), 1 of “panic disorder” and was prescribed fluoxetine, 1 of “bipolar disorder” and was prescribed fluoxetine, 1 of “AADD” and was prescribed an unspecified AADD medication, and 1 of “anxiety” and was prescribed paroxetine; and B) 3 had used an antidepressant without any indication of psychiatric diagnosis (2 of them were taking sertraline and 1 an unspecified antidepressant). Also, one pilot had a history of alcohol abuse and one of depression (no use of medication). In the CAMI aeromedical certification records, however, unconsciousness (no use of an SSRI) and anxiety (use of sertraline) were reported in only 2 of the total 13 (11 1 2) pilots.

Based on the information available in the NTSB Database, accident reports of all 61 SSRI-involved accidents have been finalized. Accordingly, 19 of the 61 accidents wherein drug and ethanol use and/or medical conditions were determined to be the probable cause and/or contributing factors are summarized in Table I (For a longer version, see Table A ). The probable cause of one accident was undetermined. The cause/factor(s) of the remaining 41 accidents were not associated with drug

and/or ethanol use and/or medical conditions. As summarized in Table I , the use of drugs (an SSRI or other drugs) was found to be the probable cause of 2 accidents and a contributing factor in 12. Also, the use of alcohol was reported to be the cause of three accidents and a contributing factor in one. Psychological conditions were found to be a contributing factor in four accidents. In one accident, the pilot’s drug use and depression was reported as a finding.

DISCUSSION

The use of SSRIs by aviators has attracted a great deal of discussion ( 16,17,23,26 ), and some authors and professional associations recommended a policy for developing criteria to allow the use of the antidepressants by selected pilots (17). Currently, U.S. regulations do not permit the use of antidepressants by civilian aviators (12,14). Nevertheless, some countries have different policies about SSRI use by aviators. For example, Canadian aviation authorities have an aeromedically supervised treatment protocol that allows a small number of pilots to fl y “with or as copilots” during maintenance

during January 1993 – June 2004 nearly 500 pilots and air traffic controllers to return to duty while their depression was under control with SSRIs (13,21). Although ACASA’s experience of antidepressant use ( 13,21 ) has been documented, safety concerns have been raised about the details of the associated procedures and the need for additional data has been suggested (15).

TABLE I. DRUG AND ETHANOL USE AND/OR MEDICALCONDITIONS AS THE CAUSE AND FACTORS IN THE

SSRI-INVOLVED ACCIDENTS AS DETERMINED BY THE NTSB.

Accident

Probable Cause

Contributing Factor(s)

1

Suicide

Other psychological condition

2

—

Use of prescription drug

3

Alcoholic and drug impairment ofefficiency and judgment

4

—

Impairment due to use of drugs that were not approved for use while flying

5

Impairment of judgment and performancedue to drugs

6

Loss of control due to spatial disorientation

Impairment due to medication

7

—

Use of contraindicated drugs

8

Use of unapproved medication

9

Physiological impairment due toalcohol

Psychological condition

10

—

Impairment of the pilot’s judgmentby the use of a contraindicated drug, and his overconfidence in his abilities

11

—

Use of prescription drugs not approved for use by the FAA

12

Alcohol-impaired decision making

13

The pilot’s incapacitation

Inappropriate use of medication,and depression *

14

—

Impairment due to drugs/medication

15

—

Pilot’s impairment (alcohol), andhis psychological condition

16

——

——

Drug impairment of the pilot as aresult of higher than normal

levels of Benadryl

17

Use of FAA prohibited drugs

18

Impairment (drugs) of the privatepilot

19

Use of inappropriate medications

* Findings

The grouping of 61 SSRI pilots is based upon the post-mortem toxicological findings of U.S. civil aviation accidents, 1990 – 2001 ( 1,2 ). Although only 1 of the 4 SSRIs was found in 22 pilots, amphetamines and other sympathomimetics, antihistaminics, benzodiazepines, butalbital, cocaine, narcotic and non-narcotic analgesics, quinine, and/or tetrahydrocannabinol carboxylic acid, verapamil, and/or ethanol were also found in the remaining 39 SSRI pilots ( 1,2 ). However, this study did not contain information on the medical history of these airmen. In continuation of the previous postmortem analytical findings, the present study found that none of the 61 pilots was certificated mistakenly. Although 88% (52/59) of the pilots had not reported their psychiatric condition and 95% (56/59) had never reported the use of an antidepressant, the higher percentage of reporting of a DUI — 39% (23/59) — was an interesting observation.

The reporting of DUIs in such relatively high numbers, compared to the reporting of SSRI use, could have been because the FAA has the authority to access the records of pilots from the National Driver Registry. Also, some pilots may have assumed that they could continue to fly even with a history of DUI. This observation might support the suggestion that a policy allowing a supervised maintenance SSRI use could prevent airmen from using SSRIs without informing the FAA (16,17). However, the use of SSRIs may be underreported, similar to the situation in which only 1% of Australian pilots were identified as having been certifi cated while taking SSRIs (21).

The 1% value was considered to be much lower than that of the general population, suggesting that the SSRI use was underreported. Overall, current findings suggest that the majority of the SSRI-involved fatal aviation accident pilots were certificated and they were primarily private pilot and third-class medical certificate holders. However, there were a number of pilots who chose to fl y without fl ying

and medical certificates. In the group of 61, there were experienced and inexperienced aviators, ranging from young to old age groups. Although the presence of SSRIs in the aviators was analytically demonstrated, their use was not reported in the last aeromedical examinations of the aviators. Additionally, most of the airmen had not self-reported their psychological conditions and medications while they were continuing a regular SSRI treatment. Even the pilots with medical backgrounds

and education, for example, psychiatry and psychology, did not report their medical conditions or medications. Therefore, AMEs should use caution in certifying airmen with unreported psychological symptoms or signs, particularly when the use of this group of antidepressants is drastically increasing in the society.

ACKNOWLEDGMENTS

This document is disseminated under the sponsorship of the U.S. Department of Transportation in the interest of information exchange. The United States Government assumes no liability for the contents thereof. The work included in this paper was conducted in a U.S. Government facility and has been produced as an internal technical report of the Office of Aerospace Medicine, Federal Aviation Administration, U.S. Department of Transportation, Washington, DC (Report No.: DOT/FAA/AM-07/19).

The Government of Turkey is acknowledged for allowing the participation of Dr. Ahmet Akin and Dr. Ahmet Sen in the Federal Aviation Administration (FAA) International Exchange Visitor Program at the FAA Civil Aerospace Medical Institute, Oklahoma City, OK. The authors are grateful to Dr. Selim Kilic, Department of Epidemiology, Gülhane Military Medical Academy, Ankara, Turkey, for performing statistical analyses.